text: /*
   * @lc app=leetcode id=137 lang=javascript
   *
   * [137] Single Number II
   */
  /**
   * @param {number[]} nums
   * @return {number}
   */
  var singleNumber = function(nums) {
    // [1,1,1,2]
    let res = 0;
    // 前提是nums中数字都不大于2^31
    for (let i = 0; i < 32; i++) {
      let cnt = 0;
      let bit = 1 << i;
      for (let j = 0; j < nums.length; j++) {
        if (nums[j] & bit) cnt++;
      }
      if (cnt % 3 != 0) res = res | bit;
    }
    return res;
  };
  